How to speed up grid when using if statement for choose the operation in view (image)

I would like to speed up this simple code that gets slow when I hit the "Cancella/Seleziona" button in the navigation bar, because it redraws the grid even though ThumbnailView(asset: asset, size: 150) is still the same.

import SwiftUI
import Photos

struct ContentView: View {

    @State private var theId = 0

    @State private var showCancelOrSelected = true

    @ObservedObject var photos = PhotosModel()

    private var adaptiveLayout = [GridItem(.adaptive(minimum: 150))]

    var body: some View {
        NavigationView{
            ScrollView(.vertical, showsIndicators: false, content: {
                LazyVGrid(columns: adaptiveLayout, spacing: 5) {
                    ForEach(photos.allAssets) { asset in
                        if showCancelOrSelected {
                            NavigationLink(destination: DetailImageView(asset: asset)) {
                                ThumbnailView(asset: asset, size: 150)
                                    .equatable()
                            }
                        } else {
                            ThumbnailView(asset: asset, size: 150)
                                .equatable()
                        }
                    }
                    .id(theId)
                }
            })
            .navigationBarTitle("ULTIME \(photos.allAssets.count) FOTO", displayMode: .inline)
            .toolbar {
                ToolbarItemGroup(placement: .navigationBarTrailing) {
                    Button(showCancelOrSelected ? "Cancella" : "Seleziona") {
                        showCancelOrSelected.toggle()
                        theId += 1
                        print("showCancelOrSelected: \(showCancelOrSelected)")
                    }
                }
            }
        }
        .navigationViewStyle(StackNavigationViewStyle())
    }
}

I tried making ThumbnailView compatible with Equatable protocol like this and adding .equatable (), but to no avail.

struct ThumbnailView: View, Equatable {

    let asset:PHAsset
    let size:Int

    var body: some View {
        Image(uiImage: imageFromAsset(asset: asset, size: size))
            .resizable()
            .frame(width: CGFloat(size), height: CGFloat(size))
    }

    static func == (lhs: ThumbnailView, rhs: ThumbnailView) -> Bool {
        return lhs.size == rhs.size && lhs.asset == rhs.asset
    }
}

Can anyone tell me how to prevent the grid from being redesigned?